The present invention relates to holographic disk mounting systems and, more particularly, to a method and apparatus for mounting a holographic disk on a spin motor shaft which utilizes the radial expansion of an axially compressed O-ring to eliminate clearance between the holographic disk and spin motor shaft.
Holographic spinners are used for scanning a laser beam across a surface for purposes of writing or reading. The rapidly spinning holographic disk imposes a number of constraints upon the designer. The disk must be maintained in accurate perpendicular alignment with the axis of rotation and must also have zero radial play in order to preserve dynamic balance of the assembly. Various holographic disk mounting systems have been proposed in the art. For example, U.S. Pat. No. 4,353,615 discloses a dynamic mounting system for holographic spinners utilizing a self-aligning bearing while U.S. Pat. No. 4,556,278 discloses a free-floating mount for a holographic disk. In both patents, the centrifugal force developed by rotation of the disk is employed to align the disk with the axis of rotation. In each case, the mounting systems are relatively complex and, therefore, expensive.
It is, accordingly, a general object of the present invention to provide an improved method and mounting system for holographic disks.
It is a specific object of the invention to provide a holographic disk mounting system and method that provides precise perpendicular alignment of the disk to the axis of rotation while achieving zero radial play.
It is another object of the present invention that the mounting system imposes minimum stresses in the holographic disk.
It is a still further object of the present invention to provide a method and apparatus for holographic disk mounting which permits positive, repeatable disk alignment.
It is a feature of the invention that the mounting system utilizes inexpensive simple parts to achieve the desired objectives of precise perpendicular alignment and zero radial play.
It is another feature of the invention that the mounting system can be used over a wide range of temperatures.